Prevalence and Risk Factors of Bone and Dental Lesions in Neotropical Deer.

Bone and dental lesions have been documented in various deer species globally, affecting the efficiency of ingestion and digestion, consequently influencing their general health and leading to a decline in survival and reproductive performance. The present study aimed to characterize bone and dental lesions in the dry skulls of individual deer, estimate the prevalence of these lesions, and assess potential risk factors associated with the development of bone and dental alterations. This study assessed bone and dental lesions in 180 dry skulls of eleven neotropical deer species, originating from both captivity and wildlife conditions, through direct visual inspection. A high prevalence of bone and dental lesions was observed in all analyzed species. Dental calculus was the most common alteration (96.7%), followed by dental wear (71.1%). Animal age positively correlated with most bone and dental alterations, indicating that older animals showed more lesions. Additionally, the prevalence of these alterations was similar between sexes. Moreover, all lesions were more common in captive-bred animals, likely attributed to their older age and a less diverse diet. Blastocerus dichotomus and Mazama americana were most affected by bone resorption and dental trauma and had the highest dental calculus prevalence, along with Subulo gouazoubira and Passalites nemorivagus. All eleven species evaluated in the present study were susceptible to the occurrence of bone and dental lesions. Therefore, monitoring oral health and diet in captivity are fundamental practices for the conservation of these species.

Co-occurrence of periodontal lesions and dental wear in incisor and masticatory teeth in two sheep flocks in Brazil.

BACKGROUND: Periodontitis and tooth wear are multifactorial diseases with distinct etiopathogenesis that affect the health, feed efficiency and welfare of sheep. METHODS: This study evaluated the co-occurrence of tooth wear and periodontal lesions in 129 ewes from two Brazilian flocks, clinically classified the lesions and presence of dental calculus, and identified potential pathogens in the dental biofilm of 63 ewes by polymerase chain reaction. RESULTS: Of the 129 ewes included in the study, 75 presented periodontal lesions, while all animals presented tooth wear and dental calculus. Of the animals with periodontal lesions, 16.2% had lesions in incisor teeth and 52.7% in masticatory teeth. Regarding excessive tooth wear, 38.6% had severe wear on the incisor teeth and 89.1% on the masticatory teeth. Ewes older than 36 months had a higher frequency of periodontal lesions in incisor teeth (p < 0.001) and a greater amount of dental calculus (p < 0.001), but there was no association between tooth wear and animal age. Fusobacterium nucleatum, Tannerella forsythia and Fusobacterium necrophorum predominated in periodontal lesions. LIMITATION: This study is limited by the small sample size and lack of diagnostic imaging to assess periodontal disease. CONCLUSION: The co-occurrence of periodontal lesions and excessive dental wear involving both the incisor and masticatory teeth suggests that although the two diseases have different aetiologies, they likely have common risk factors.

Gingivitis in cattle and supplemental protein diet: Insights from proteomic analysis.

Salivary proteins are essencial in the maintenance of oral homeostasis and can reflect systemic and localized processes, like gingivitis. However, little is known about the relationship between diet and the occurrence of gingivitis in cattle. The present study aimed to characterize the salivary proteomic profile of cattle (n = 12) fed hay (112.19 g/kg of crude protein) cultivated in reformed pastures, and, one group received protein supplement (PS, n = 6); the effect of the protein supplement on the gingival health of the cattle was determined by weekly intraoral examination and periodontal evaluation of the eight (deciduous) incisors. The whole saliva proteome of the two groups was evaluated after 20 and 60 days of confinement. In the periodontal clinical evaluation both groups had episodes of gingivitis; however, the average number of affected sites in the PS group was higher on day 60. The cattle fed exclusively hay, presented a lower average of affected gingival sites on day 60. After 60 days of experimentation, nine biological and 11 immunological processes were altered in bovine saliva. Proteins with multiple functions were detected in the saliva of the cattle; however, differences were observed in their regulation between the two groups. SIGNIFICANCE: In bovine populations, the relationship between diet and increased incidence of gingivitis is theorized. The results of the present pilot study, both diets caused episodes of gingivitis in the primary dentition of cattle and, apparently, diets with protein supplementation stimulate the expression of salivary proteins with a protective role in cattle that can act against infectious-inflammatory processes, such as gingivitis. However, it is plausible that over time, cattle will adapt to these diets and become more vulnerable to gingivitis.

Soil type determines the magnitude of soil fertility changes by forest-to-pasture conversion in Western Amazonia.

The deforestation of tropical forests raises environmental concerns worldwide. Removing the pristine forest impacts the soil, consequently affecting the environmental services it provides. Within this context, the main goal of this study was to determine how the conversion of the tropical rainforest to pasture affects soil fertility across an extended range of soil heterogeneity, including different soil types. We sampled 13 sites, among forests, recent pastures (≤7-year-old), and old pastures (≥10-year-old), on Acrisols, Ferralsols, Plinthosols, and Luvisols, across a ± 800 km geographical range in the Western Brazilian Amazon. Soils were classified taxonomically, and their superficial layer's chemical and physical properties (0-10 cm) were analyzed. Furthermore, we tested the sensibility of Actinobacteria and Proteobacteria to detect changes in these soil properties based on their ecological habitat. An inter-regional gradient of soil fertility was observed, and the sampling sites were clustered mostly by soil type and associated land use than by spatial distance. The Sum of bases, Ca + Mg, base saturation, Al saturation, and pH were consistently affected by land use, increasing after conversion to pasture, at different degrees and with a more pronounced effect on oxidic soils. The Sum of bases was the only property that increased significantly among the study sites (Radj = 0.860, p < 0.001), being able to detect the effect of anthropic land use on a larger coverage of soil types. Finally, the Actinobacteria:Proteobacteria ratio was also sensitive to the impact of forest-to-pasture conversion, with a higher ratio observed in pasture systems, and it was positively correlated with soil pH (rho = 0.469, p < 0.001). Our results consistently show that the forest-to-pasture conversion leads to strong alterations in the soil environment, with varying intensities depending on soil type.

Dysbiosis and Predicted Functions of the Dental Biofilm of Dairy Goats with Periodontitis.

Periodontitis is a polymicrobial biofilm-induced inflammatory disease associated with a dysbiotic microbial community and severely affects the health and welfare of animals. However, little is known regarding the dental microbiota associated with this disease in goats. In this study, we used high-throughput sequencing, network analysis, and predicted functions to investigate the microbiota of clinically healthy goats and those with periodontitis and identify possible pathogens and proteins associated with the disease. Dental microbiomes of goats with periodontitis were richer, and network analyses showed that the number of negative interactions was higher in the networks of animals with periodontitis. Based on the interrelationships, Porphyromonas, Fusobacterium, and Prevotella were suggested to play an important role in the dental microbiota associated with goat periodontitis. Protein families linked to translation, cytoplasmatic translation, and rRNA processing were more abundant in the dental microbiota of goats with periodontitis. In conclusion, the dental biofilm microbiota associated with goat periodontitis seems to be dysbiotic and has significant antagonistic interactions, which discriminate healthy animals from diseased animals and highlight the importance of key bacteria. Thus, these novel findings contribute to the evolution of knowledge regarding the etiopathogenesis of goat periodontitis and possibly to the development of periodontitis control measures.

Monitoring periodontal lesions and their effects during pregnancy: microbiological aspects of the oral cavity and amniotic fluid in pregnant ewes / Monitoramento de lesões periodontais e seus efeitos na gestação: aspectos microbiológicos da cavidade bucal e líquido amniótico de ovelhas gestantes

Periodontitis affects the teeth supporting tissues, leading to tooth loss and damage to animal health. Evidence in humans suggests that oral microorganisms spread systemically, increasing the risk of pregnancy disorders such as miscarriage, prematurity, and low birth weight. This study aimed to verify whether periodontopathogenic microorganisms reach the transplacental unit, culminating in problems in pregnant ewes. After analyzing the oral cavity, 10 clinically healthy pregnant ewes (OGCH group) and 10 pregnant ewes with periodontitis (OGP group) were selected. The subgingival biofilm was collected for the polymerase chain reaction (PCR) test and amniotic fluid for both the PCR and interleukin (IL) analysis. Peripheral blood was collected for complete blood count, and analyses of IL-6, IL1-ß, and tumor necrosis factor-α were performed. Placental fragments were collected to assess the inflammatory changes using optical microscopy. After giving birth, both the ewes and their lambs were weighed. On clinical examination, a positive correlation between bleeding and suppuration (correlation index - CI=0.54), suppuration and marginal gingivitis (CI=0.34), and marginal gingivitis and edema (CI=0.54) was observed. The weights of the ewes (p=0.013) and their respective lambs (p=0.04) in the OGP group were lower than those of their OGCH group counterparts. The hematological analysis revealed that the OGP group ewes showed a slight increase in the mean corpuscular volume (p=0.2447), segmented cells (p=0.3375), and eosinophils (p=0.3823) when compared with the OGCH group ewes, without a statistical difference. Regarding the microorganisms detected in the oral cavity, there was a significant difference between the occurrence of periodontal pockets and the presence of Fusobacterium necrophorum (p=0.0328), Porphyromonas asaccharolytica (p=0.0392), and the Mollicutes class (p=0.0352). Staphylococcus genus (p=0.9107) and Archaea domain (p=0.7245) were detected in the amniotic samples of both groups, without a significant difference, whereas P. asaccharolytica (p=0.2685) was only detected in one sample in the OGCH group. The expression of cytokine IL-6 in the OGP group differed significantly between the prepartum and postpartum periods (p=0.0039); moreover, it differed significantly in the postpartum period between the OGCH and OGP groups (p=0.0198). Histological examination showed a higher percentage of placental changes in the OGP group (70%) than in the OGCH group, such as the presence of macrophages, neutrophils, plasma cells, and multifocal areas of calcification. These results do not corroborate the hypothesis of dissemination of oral microorganisms to the placental unit, suggesting that it constitutes placental isolation in sheep.

A periodontite afeta os tecidos de suporte dos dentes levando à perda dentária e danos à saúde do animal. Evidências em humanos sugerem que os microrganismos orais se espalham sistemicamente, aumentando o risco de distúrbios da gravidez, como aborto espontâneo, prematuridade e baixo peso ao nascer. Este estudo teve como objetivo verificar se microrganismos periodontopatogênicos atingem a unidade transplacentária, culminando em problemas em ovelhas gestantes. Após análise da cavidade oral, foram selecionadas 10 ovelhas gestantes clinicamente saudáveis (grupo OGCH) e 10 ovelhas gestantes com periodontite (grupo OGP). O biofilme subgengival foi coletado para o teste de reação em cadeia da polimerase (PCR) e o líquido amniótico para teste de PCR e análise de interleucina (IL). Sangue periférico foi coletado para hemograma completo e análises de IL-6, IL1-ß e fator de necrose tumoral-α foram realizadas. Fragmentos de placenta foram coletados para avaliação das alterações inflamatórias por meio de microscopia óptica. Após o parto, as ovelhas e seus cordeiros foram pesados. Ao exame clínico, observou-se correlação positiva entre sangramento e supuração (índice de correlação - IC=0,54), supuração e gengivite marginal (IC=0,34) e gengivite marginal e edema (IC=0,54). Os pesos das ovelhas (p=0,013) e de seus respectivos cordeiros (p=0,04) do grupo OGP foram inferiores aos do grupo OGCH. A análise hematológica revelou que as ovelhas do grupo OGP apresentaram discreto aumento no volume corpuscular médio (p=0,2447), células segmentadas (p=0,3375) e eosinófilos (p=0,3823) quando comparadas com as ovelhas do grupo OGCH, sem diferença estatística diferença. Em relação aos microrganismos detectados na cavidade oral, houve diferença significativa entre a ocorrência de bolsas periodontais e a presença de Fusobacterium necrophorum (p=0,0328), Porphyromonas asaccharolytica (p=0,0392) e da classe Mollicutes (p=0,0352). O gênero Staphylococcus (p=0,9107) e o domínio Archaea (p=0,7245) foram detectados nas amostras amnióticas de ambos os grupos, sem diferença significativa, enquanto P. asaccharolytica (p=0,2685) foi detectado apenas em uma amostra do grupo OGCH. A expressão da citocina IL-6 no grupo OGP diferiu significativamente entre os períodos pré e pós-parto (p=0,0039); além disso, diferiu significativamente no período pós-parto entre os grupos OGCH e OGP (p=0,0198). O exame histológico mostrou maior porcentagem de alterações placentárias no grupo OGP (70%) do que no grupo OGCH, como a presença de macrófagos, neutrófilos, plasmócitos e áreas multifocais de calcificação. Esses resultados não corroboram a hipótese de disseminação de microrganismos orais para a unidade placentária, sugerindo que se trata de um isolamento placentário em ovinos.

Gingivitis in calves: longitudinal hematological and metabolic profiles- and salivary buffering capacity in animals treated with virginiamycin / Gengivites em bezerros: perfis longitudinais hematológicos, metabólicos e capacidade tamponante salivar em animais tratados com virginiamicina

Gingivitis is an infectious inflammatory process that generates local and systemic conditions, compromising the masticatory capacity of animals. Virginiamycin controls and prevents gingivitis and necrotizing gingivitis in cattle. However, the interaction and effect with different sera and salivary elements remain unknown. The present 6-month longitudinal study evaluated the hematological, metabolic, and salivary buffering capacity profiles of calves with gingivitis treated with virginiamycin. Ten calves were divided into two groups: control and virginiamycin (n = 5 each). Calves in the virginiamycin group had a lower occurrence of gingivitis (P < 0.01, Student's t-test). The animals that developed gingivitis in both experimental groups had higher salivary levels of alkaline phosphatase (P = 0.01915) and lower serum levels of albumin (P = 0.0028). Additionally, animals receiving virginiamycin had higher serum levels of magnesium (P = 0.008), albumin (P = 0.0008), urea (P = 0.008), alkaline phosphatase (P = 0.008), total proteins (P = 0.008), and plasma protein (P = 0.018). Salivary buffering capacity was negatively correlated with salivary variables such as calcium, magnesium, albumin, total protein, and aspartate aminotransferase and serum variables such as albumin and aspartate aminotransferase. Results of the present study suggested that the occurrence of periodontopathies in episodes is reflected in the local and systemic alterations in animals. In this context, clinical periodontal monitoring also showed the benefits of virginiamycin supplementation on gingival conditions and systemic health markers, in addition to controlling the two precursor forms of periodontitis.

Gengivites são processos infecto-inflamatórios que geram quadros locais e sistêmicos, com comprometimento da capacidade mastigatória dos animais. A virginiamicina controla e previne a gengivite e a gengivite necrosante em bovinos; no entanto, a interação e efeito com diferentes elementos séricos e salivares permanecem desconhecidos. O presente estudo teve como objetivo avaliar, em um estudo longitudinal com duração de seis meses, os perfis hematológicos, metabólicos e de capacidade tamponante salivar de bezerros com gengivite e tratados com virginiamicina. Foram utilizados 10 bezerros divididos em dois grupos: grupo controle (n = 5) e grupo virginiamicina (n = 5). Os bezerros do grupo virginiamicina apresentaram menor ocorrência de gengivite (P < 0,01, teste T - Student). Os animais que desenvolveram gengivite, de ambos os grupos experimentais, apresentaram níveis salivares mais elevados de fosfatase alcalina (P = 0,01915) e níveis séricos menores de albumina (P = 0,0028). Observou-se também que os animais que receberam virginiamicina apresentaram níveis séricos mais elevados de magnésio (P = 0,008), albumina (P = 0,0008), ureia (P = 0,008), fosfatase alcalina (P = 0,008), proteínas totais (P = 0,008) e proteína plasmática (P = 0,018). As análises de capacidade tamponante salivar foram correlacionadas negativamente às variáveis salivares como cálcio, magnésio, albumina, proteína total e aspartato aminotransferase e às variáveis séricas como a albumina e aspartato aminotransferase. Os resultados do presente estudo sugerem que a ocorrência em episódios das periodontopatias refletem-se em alterações locais e sistêmicas nos animais. Neste contexto, o monitoramento clínico periodontal também evidenciou os benefícios do emprego de suplementação pela virginiamicina sobre as condições gengivais e marcadores sistêmicos de saúde, além do controle das duas formas precursoras de periodontites.

Dysbiosis and predicted function of dental and ruminal microbiome associated with bovine periodontitis.

Extensive cattle livestock is advancing in Amazonia and its low productivity, with consequent pressure to open new areas, is partly due to sanitary problems and, among them, the periodontal diseases, whose environmental triggers or modifying factors are unknown. In this study, we used high-throughput sequencing, network analysis and predicted functions to investigate the dental and ruminal microbiota of cattle raised in new livestock areas in the Amazon and identify possible keystone pathogens and proteins associated with the disease. Ninety-three genera were common in dental and ruminal fluid microbiomes and among them periodontal pathogens such as Fusobacterium, Prevotella, Porphyromonas and Actinomyces were recognized. Network analysis showed that dental microbiomes of clinically healthy animals tend to comprise a group of OTUs in homeostasis and when analyzed together, dental and ruminal fluid microbiomes of animals with periodontitis had almost twice the number of negative edges, indicating possible competition between bacteria and dysbiosis. The incisor dental and ruminal fluid microbiomes were dominated by a core community composed of members of the phyla Firmicutes and Bacteroidetes. Network results showed that members of the Prevotella genus stood out among the top five OTUs, with the largest number of hubs in the dental and ruminal microbiota of animals with periodontitis. Protein families linked to an inflammatory environment were predicted in the dental and ruminal microbiota of cattle with periodontitis. The dissimilarity between dental microbiomes, discriminating between healthy cattle and those with periodontitis and the identification of possible key pathogens, represent an important reference to elucidate the triggers involved in the etiopathogenesis of bovine periodontitis, and possibly in the development of measures to control the disease and reduce the pressures for deforestation.

Oral affections in an ex situ population of marsh deer (Blastocerus dichotomus): a retrospective study (1990-2020) / Afecções bucais em uma população ex situ de cervos-do-pantanal (Blastoceru dichotomus): um estudo retrospectivo (1990-2020)

Oral diseases are limiting to health, welfare, and conservation practices, especially in the case of endangered animals. In this retrospective study, a survey on oral health-related conditions noted in the clinical records for 261 deer comprised in an ex situ population of the Marsh Deer Conservation Center (CCCP) over 30 years (1990-2020) was carried out. Of these, 49 (18.77%) marsh deer (31 females - 63.27% and 18 males - 36.73%) had clinical oral affections; the affected deer's mean age was 8.9 years. Logistic regression analysis was performed, and the variable age was significantly associated with the presence of dental affections. Thus, with a change in the age category, a deer had eight times the chance of manifesting oral affections; therefore, age can be considered a risk factor for the manifestation of oral affections in the species. Increased facial volume (65.3%), accumulation of food in the mouth (36.7%), tooth loss (22.4%), fistulas (22.4%), mucosal or palatal lesions (22.4%), tooth wear (20.4%), and tooth root exposure (18.3%) were the most frequently recorded lesions. The relatively high occurrence of oral affections in Blastocerus dichotomus reiterates the importance of oral health care when deer are kept in human care.

As doenças bucais são limitantes para as práticas de saúde, bem-estar e conservação, especialmente no caso de animais ameaçados de extinção. Neste estudo retrospectivo, realizou-se um levantamento sobre condições relacionadas à saúde bucal observadas nos registros clínicos de 261 cervídeos que compunham uma população ex situ do Centro de Conservação do Cervo-do-Pantanal durante um período de 30 anos (1990-2020). Destes, 49 (18,77%) cervos-do-pantanal (31 fêmeas (63,27%) e 18 machos (36,73%)) apresentavam afecções clínicas bucais; e a idade média dos cervídeos afetados foi de 8,9 anos. Realizou-se a análise de regressão logística e a variável idade mostrou associação significativa com a presença de afecções dentárias. Assim, com a mudança de categoria de idade, um cervídeo teve oito vezes mais chances de manifestar afecções bucais; portanto, a idade pode ser considerada como fator de risco para manifestação de afecções bucais na espécie. Aumento de volume facial (65,3%), acúmulo de alimentos na boca (36,7%), perda dentária (22,4%), fístulas (22,4%), lesões nas mucosas ou palatinas (22,4%), desgaste dentário (20,4%) e exposição de raiz (18,3%) foram as lesões mais registradas. A ocorrência relativamente alta de afecções bucais em Blastocerus dichotomus reitera a importância dos cuidados com a saúde bucal quando os cervídeos são mantidos sob cuidados humanos.

Type C botulism in dogs from rural properties located in Goiânia, Brazil

Botulism is a disease usually fatal, caused by the ingestion of neurotoxins produced by Clostridium botulinum. In dogs, intoxication is caused by the ingestion of botulinum toxin type C, and animals often recover spontaneously. The present study describes the occurrence of type C botulism in two dogs domiciled on neighboring rural properties in the municipality of Goiânia, state of Goiás, Brazil, probably associated with ingestion of decomposing bovine carcass. Upon clinical evaluation, the dogs were alert in the lateral decubitus position with ascending flaccid paralysis, absence of eyelid reflexes, and reduced muscle tone. Due to their worsening clinical symptoms, the animals died within 12 h and 3 days after supportive treatment. Botulinum toxin type C was identified, in the serum and feces of both dogs, by seroneutralization in mice with homologous monovalent antitoxin. The results of the high-throughput gene sequencing showed that the abundance of C. botulinum in the fecal microbiota of one of the affected dogs was low (0.53%). In this way, the present study highlights the need of sanitary practices related to the appropriate collection and disposal of bovine carcasses in rural areas since they represent a risk factor for the occurrence of botulism in dogs domiciled on rural properties.

Type C botulism outbreak in free-ranging waterfowl in Goiás / Surto de botulismo tipo C em aves aquáticas de vida livre em Goiás

Botulism is generally a fatal disease caused by ingestion of neurotoxins produced by Clostridium botulinum. The present study describes the epidemiological, clinical, and laboratory aspects of a type C botulism outbreak in free-living aquatic birds residing in an urban park in Quirinópolis, Goiás, Brazil. Among a population of approximately 80 waterfowl, a total of 30 birds, including ducks (Cairina moschata), teals (Anas platyrhynchos), and geese (Anser cygnoides), died within 10 days. Of these, six birds showed signs of flaccid paralysis of the pelvic limbs, eyelids, neck, and wings. To confirm the suspicion of botulism, four lake water samples, two samples of the feed consumed by the birds, and samples of serum, intestinal content, stomach content, and liver tissue from two teals that died after presenting clinical signs were analyzed. Using bioassay and neutralization with homologous antitoxin in mice, it was possible to detect the presence of botulinum toxin type C in a water sample and in the intestinal content of one of the necropsied teals. Additionally, the presence of C. botulinum type C was identified in the lake water using polymerase chain reaction. Based on the clinical signs and laboratory results, a diagnosis of botulism caused by botulinum toxin type C was confirmed with probable transmission by lake water.

O botulismo é uma doença geralmente fatal, causada pela ingestão de neurotoxinas produzidas pelo Clostridium botulinum. O presente estudo descreve os aspectos epidemiológicos, clínicos e laboratoriais de um surto de botulismo tipo C em aves aquáticas de vida livre habitantes de parque urbano em Quirinópolis, Goiás. De uma população de cerca de 80 aves aquáticas, um total de 30 aves, entre patos (Cairina moschata), marrecos (Anas platyrhynchos) e gansos (Anser cygnoides), morreram no intervalo de 10 dias. Destes, seis aves apresentaram sinais de paralisia flácida de membros pélvicos, pálpebras, pescoço e asas. Para confirmar a suspeita de botulismo, foram analisadas quatro amostras da água do lago, duas amostras da ração consumida pelas aves e amostras de soro, conteúdo intestinal, conteúdo estomacal e fígado de dois marrecos que morreram após apresentarem os sinais clínicos. Pelo bioensaio e neutralização com antitoxina homóloga em camundongos foi possível detectar a presença de toxina botulínica tipo C em uma amostra de água e no conteúdo intestinal de um dos marrecos necropsiados. Adicionalmente, pela reação em cadeia da polimerase identificou-se a presença de C. botulinum tipo C na água do lago. Com base nos sinais clínicos e resultados laboratoriais estabeleceu-se o diagnóstico de botulismo causado pela toxina botulínica tipo C e veiculada provavelmente pela água do lago.

Pathology of chronic ovine periodontitis / Patologia da periodontite crônica em ovinos

Periodontitis is an inflammatory process of infectious origin affecting the teeth and their supporting structures, causing significant economic losses and reducing animal welfare. Bacteria in the gingival biofilm are one of the main factors in initiating inflammatory lesions. Bacteria act directly on tissues or indirectly through substances that cause tissue damage. Studies on the etiopathogenesis of periodontitis in Brazilian sheep herds are scarce. The present study aimed to characterize histologically periodontal lesions of culled sheep from the Brazilian breed, Santa Inês. Periodontal lesions, such as periodontal pockets containing plant tissue and bacteria, replacement of the periodontal ligament by connective tissue and inflammatory cells, superficial pustules, hydropic epithelial degeneration, and epithelium hyperplasia, were observed. Submucosal changes were characterized by granulation tissue, edema, swelling of the endothelial cells, bacteria, and predominantly perivascular lymphoplasmacytic inflammatory infiltrate. In the alveolar bone, osteoclastic resorption and bone apposition were observed. This study revealed subacute to chronic inflammation, alveolar bone resorption, and cortical bone apposition in ovine periodontitis. Thus, these findings can contribute to the evolution of knowledge about the etiopathogenesis of ovine periodontitis and, possibly, the development of measures to control the disease.

A periodontite é um processo inflamatório de origem infecciosa que afeta os dentes e suas estruturas de suporte, causando perdas econômicas significativas e redução do bem-estar animal. As bactérias do biofilme gengival são um dos principais fatores envolvidos no início das lesões inflamatórias. As bactérias agem diretamente nos tecidos ou indiretamente por meio de substâncias que causam dano tecidual. Estudos sobre a etiopatogenia da periodontite em rebanhos ovinos brasileiros são escassos. O presente estudo teve como objetivo caracterizar histologicamente as lesões periodontais de ovinos de descarte da raça brasileira Santa Inês. Foram observadas lesões periodontais, como bolsas periodontais contendo tecido vegetal e bactérias, substituição do ligamento periodontal por tecido conjuntivo e células inflamatórias, pústulas superficiais, degeneração hidrópica epitelial e hiperplasia do epitélio. As alterações da submucosa foram caracterizadas por tecido de granulação, edema, tumefação das células endoteliais, bactérias e infiltrado inflamatório linfoplasmocitário predominantemente perivascular. No osso alveolar, observou-se reabsorção osteoclástica e aposição óssea. Este estudo revelou inflamação subaguda a crônica, reabsorção óssea alveolar e aposição de osso cortical na periodontite ovina. Assim, esses achados podem contribuir para a evolução do conhecimento sobre a etiopatogenia da periodontite ovina e para o desenvolvimento de medidas de controle da doença.

Dental biofilm and its ecological interrelationships in ovine periodontitis.

Introduction. Periodontitis, one of the most common oral disorders in sheep, is caused by a mixed and opportunistic microbiota that severely affects the health and welfare of animals. However, little is known about the ecological processes involved and the composition of the microbiota associated with the development of the disease.Hypothesis/Gap Statement. Using high-throughput sequencing of the 16S ribosomal RNA gene and network analysis it would be possible to discriminate the microbiomes of clinically healthy sheep and those with periodontitis and possibly identify the key microorganisms associated with the disease.Aim. The present study aimed to characterise the composition of dental microbiomes and bacterial co-occurrence networks in clinically healthy sheep and animals with periodontitis.Methodology. Dental biofilm samples were collected from ten sheep with periodontitis and ten clinically healthy animals. Bacteria were identified using high-throughput sequencing of the 16S ribosomal RNA gene.Results. The most prevalent genera in the dental microbiota of sheep with periodontitis were Petrimonas, Acinetobacter, Porphyromonas and Aerococcus. In clinically healthy animals, the most significant genera were unclassified Pasteurellaceae, Pseudomonas, and Neisseria. Fusobacterium was found at high prevalence in the microbiomes of both groups. The dental microbiota of sheep in the two clinical conditions presented different profiles and the diversity and richness of bacteria was greater in the diseased animals. Network analyses showed the presence of a large number of antagonistic interactions between bacteria in the dental microbiota of animals with periodontitis, indicating the occurrence of a dysbiotic community. Through the interrelationships, members of the Prevotella genus are likely to be key pathogens, both in the dental microbiota of healthy animals and those with periodontitis. Porphyromonas stood out among the top three nodes with more centrality and the largest number of hubs in the networks of animals with periodontitis.Conclusion. The dental biofilm microbiota associated with ovine periodontitis is dysbiotic and with significant antagonistic interactions, which discriminates healthy animals from diseased animals and highlights the importance of key bacteria, such as Petrimonas, Porphyromonas, Prevotella and Fusobacterium species.

Land-Use System and Forest Floor Explain Prokaryotic Metacommunity Structuring and Spatial Turnover in Amazonian Forest-to-Pasture Conversion Areas.

Advancing extensive cattle production is a major threat to biodiversity conservation in Amazonia. The dominant vegetation cover has a drastic impact on soil microbial communities, affecting their composition, structure, and ecological services. Herein, we explored relationships between land-use, soil types, and forest floor compartments on the prokaryotic metacommunity structuring in Western Amazonia. Soil samples were taken in sites under high anthropogenic pressure and distributed along a ±800 km gradient. Additionally, the litter and a root layer, characteristic of the forest environment, were sampled. DNA was extracted, and metacommunity composition and structure were assessed through 16S rRNA gene sequencing. Prokaryotic metacommunities in the bulk soil were strongly affected by pH, base and aluminum saturation, Ca + Mg concentration, the sum of bases, and silt percentage, due to land-use management and natural differences among the soil types. Higher alpha, beta, and gamma diversities were observed in sites with higher soil pH and fertility, such as pasture soils or fertile soils of the state of Acre. When taking litter and root layer communities into account, the beta diversity was significantly higher in the forest floor than in pasture bulk soil for all study regions. Our results show that the forest floor's prokaryotic metacommunity performs a spatial turnover hitherto underestimated to the regional scale of diversity.

First record of mass wild waterfowl mortality due to Clostridium botulinum in Brazilian semiarid.

In 2008, 270 wild birds from aquatic environments were found dead or debilitated on the banks of smaller lakes that had been formed due to the decrease in the level of the holding lake of the Sobradinho Dam located on the São Francisco River in the Caatinga of Bahia, Brazil. The outbreak occurred months after the dam's partial drainage, with the formation of puddles that accumulated decomposing organic material. Amongst the 270 individuals examined and/or found dead, the majority (50%) of the birds found belonged to the Anatidae family. The debilitated birds presented neurological clinical signs including lack of motor coordination, weakness, grave flaccid paralysis in the legs, wings, neck and eyelids, diarrhea, and dyspnea. Tissue samples of the birds were collected, as were water samples and samples of the substrate of the lakes. Zoonotic arboviroses or heavy metals were not detected. Analyses of liver and digestive tract content samples through bioassay and serum neutralization in mice revealed the presence of type C botulinic toxin in the viscerae samples, and type D in sediment samples. According to our knowledge, this is the first record of an outbreak of botulism in wild birds in natural conditions in Brazil.

Chemical and structural composition of black pigmented supragingival biofilm of bovines with periodontitis / Composição química e estrutural do biofilme supragengival pigmentado de bovinos com periodontite

Bovine periodontitis is a multifactorial disease primarily associated with a potentially pathogenic microbiota housed in the oral biofilm of animals. Biofilms are organized structures, in which the constituents coexist in symbiosis, already described as a predisposing factor to periodontitis in other species. The objective of the present study was to characterize the structure and chemical aspects of the bovine black pigmented supragingival biofilm using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively, and determine its relationship with bovine periodontitis. Eleven premolar teeth from different animals were evaluated; five non-pigmented samples and six samples with black pigmented biofilms were initially submitted to SEM, and three areas of these samples were selected for EDS. The structure of the pigmented biofilm was more complex and irregular because of a higher content of mineral elements. The semi-quantitative EDS data indicated an association of iron (p<0.014) and magnesium (p<0.001) with the occurrence of periodontitis, whereas carbon, phosphorus, calcium, manganese, sodium, and potassium were not associated with the disease. Carbon (p<0.039), manganese (p<0.007), and iron (p<0.015) were associated with pigmentation, whereas phosphorus, calcium, and magnesium were not associated with it. Spearman correlation test showed the relationships between calcium and phosphorus, and iron and silicon. The strong association of iron in the pigmented supragingival biofilm and with the occurrence of periodontitis suggests the presence of microorganisms that use this element in their metabolism and that are also associated with bovine periodontitis. This study suggests that the pigmented deposits in the crown of the teeth of cattle are an true biofilm with the deposition of iron, and it indicates that the presence of iron and magnesium in these formations may be involved in the metabolism of some microorganisms associated with the etiology of bovine periodontitis.(AU)

A periodontite bovina é uma infecção multifatorial associada primariamente à microbiota potencialmente patogênica presente no biofilme bucal. Biofilmes são estruturas organizadas, nas quais os constituintes convivem em simbiose, descritos em outras espécies como um fator predisponente à periodontite. O objetivo do presente estudo foi caracterizar estrutural e quimicamente o biofilme supragengival pigmentado de preto em bovinos, utilizando-se as técnicas de microscopia eletrônica de varredura (MEV) e espectroscopia de dispersão de energia (EDS), respectivamente, correlacionando os elementos identificados à ocorrência de periodontite e pigmentação. Foram avaliados 11 dentes primeiro-molares; cinco amostras sem pigmentação visível e seis amostras com biofilme pigmentado de preto, que foram submetidas inicialmente à MEV; posteriormente foram selecionadas três áreas aleatórias de cada dente para realização da EDS. A estrutura do biofilme pigmentado revelou formações irregulares e mais complexas, provavelmente devido ao maior acúmulo de elementos minerais. Os resultados semi-quantitativos da EDS apontaram associações entre a presença de ferro (p<0,014) e magnésio (p<0,001) com a ocorrência de periodontite. Carbono, fósforo, cálcio, manganês, sódio e potássio não apresentaram associação com a periodontite. Em relação à pigmentação, carbono (p<0,039), manganês (p<0,007) e ferro (p<0,015) foram os elementos estatisticamente significantes, enquanto fósforo, cálcio e magnésio não apresentaram associação com a pigmentação. O teste de correlação de Spearman demonstrou associações entre os elementos cálcio e fósforo, e ferro e silício. A forte associação do ferro presente no biofilme supragengival com a ocorrência de periodontite, sugere a presença de micro-organismos que utilizam este elemento em seu metabolismo e que possivelmente tenham envolvimento com o desenvolvimento da periodontite bovina. Os resultados inéditos do presente trabalho sugerem que os depósitos pigmentados que se formam na coroa dos dentes de bovinos são um biofilme verdadeiro com deposição de ferro, e indicam que a presença de ferro e magnésio nestas formações pode estar envolvida no metabolismo de alguns dos principais micro-organismos associados à etiologia da periodontite bovina.(AU)

Chemical and structural composition of black pigmented supragingival biofilm of bovines with periodontitis / Composição química e estrutural do biofilme supragengival pigmentado de bovinos com periodontite

Bovine periodontitis is a multifactorial disease primarily associated with a potentially pathogenic microbiota housed in the oral biofilm of animals. Biofilms are organized structures, in which the constituents coexist in symbiosis, already described as a predisposing factor to periodontitis in other species. The objective of the present study was to characterize the structure and chemical aspects of the bovine black pigmented supragingival biofilm using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively, and determine its relationship with bovine periodontitis. Eleven premolar teeth from different animals were evaluated; five non-pigmented samples and six samples with black pigmented biofilms were initially submitted to SEM, and three areas of these samples were selected for EDS. The structure of the pigmented biofilm was more complex and irregular because of a higher content of mineral elements. The semi-quantitative EDS data indicated an association of iron (p<0.014) and magnesium (p<0.001) with the occurrence of periodontitis, whereas carbon, phosphorus, calcium, manganese, sodium, and potassium were not associated with the disease. Carbon (p<0.039), manganese (p<0.007), and iron (p<0.015) were associated with pigmentation, whereas phosphorus, calcium, and magnesium were not associated with it. Spearman correlation test showed the relationships between calcium and phosphorus, and iron and silicon. The strong association of iron in the pigmented supragingival biofilm and with the occurrence of periodontitis suggests the presence of microorganisms that use this element in their metabolism and that are also associated with bovine periodontitis. This study suggests that the pigmented deposits in the crown of the teeth of cattle are an true biofilm with the deposition of iron, and it indicates that the presence of iron and magnesium in these formations may be involved in the metabolism of some microorganisms associated with the etiology of bovine periodontitis.(AU)

A periodontite bovina é uma infecção multifatorial associada primariamente à microbiota potencialmente patogênica presente no biofilme bucal. Biofilmes são estruturas organizadas, nas quais os constituintes convivem em simbiose, descritos em outras espécies como um fator predisponente à periodontite. O objetivo do presente estudo foi caracterizar estrutural e quimicamente o biofilme supragengival pigmentado de preto em bovinos, utilizando-se as técnicas de microscopia eletrônica de varredura (MEV) e espectroscopia de dispersão de energia (EDS), respectivamente, correlacionando os elementos identificados à ocorrência de periodontite e pigmentação. Foram avaliados 11 dentes primeiro-molares; cinco amostras sem pigmentação visível e seis amostras com biofilme pigmentado de preto, que foram submetidas inicialmente à MEV; posteriormente foram selecionadas três áreas aleatórias de cada dente para realização da EDS. A estrutura do biofilme pigmentado revelou formações irregulares e mais complexas, provavelmente devido ao maior acúmulo de elementos minerais. Os resultados semi-quantitativos da EDS apontaram associações entre a presença de ferro (p<0,014) e magnésio (p<0,001) com a ocorrência de periodontite. Carbono, fósforo, cálcio, manganês, sódio e potássio não apresentaram associação com a periodontite. Em relação à pigmentação, carbono (p<0,039), manganês (p<0,007) e ferro (p<0,015) foram os elementos estatisticamente significantes, enquanto fósforo, cálcio e magnésio não apresentaram associação com a pigmentação. O teste de correlação de Spearman demonstrou associações entre os elementos cálcio e fósforo, e ferro e silício. A forte associação do ferro presente no biofilme supragengival com a ocorrência de periodontite, sugere a presença de micro-organismos que utilizam este elemento em seu metabolismo e que possivelmente tenham envolvimento com o desenvolvimento da periodontite bovina. Os resultados inéditos do presente trabalho sugerem que os depósitos pigmentados que se formam na coroa dos dentes de bovinos são um biofilme verdadeiro com deposição de ferro, e indicam que a presença de ferro e magnésio nestas formações pode estar envolvida no metabolismo de alguns dos principais micro-organismos associados à etiologia da periodontite bovina.(AU)

Subgingival bacterial microbiota associated with ovine periodontitis / Microbiota bacteriana subgengival associada à periodontite ovina

Periodontitis is an inflammatory response in a susceptible host caused by complex microbiota, predominantly composed of Gram-negative anaerobic bacteria. Aiming to characterize the subgingival bacterial microbiota associated with ovine periodontitis, polymerase chain reaction (PCR) was performed in subgingival periodontal pocket samples of 14 sheep with severe periodontitis and in subgingival sulcus biofilm of 14 periodontally healthy sheep in search mainly of Gram-negative and Gram-positive microorganisms considered important periodontopathogens. The most prevalent bacteria in the sheep with periodontal lesions were Tannerella forsythia (78.6%), Treponema denticola (78.6%), Fusobacterium nucleatum (64.3%), and Porphyromonas gingivalis (50%), whereas in the healthy sheep, F. nucleatum (42.8%) was the most often detected bacterium. Statistically significant differences were observed for Campylobacter rectus, Enterococcus faecium, Prevotella nigrescens, T. forsythia, and T. denticola (p<0.05) in the sheep with periodontitis in the comparison between groups. Aggregatibacter actinomycetemcomitans, Enterococcus faecalis, and Porphyromonas gulae were not detected in any of the samples analyzed. In conclusion, C. rectus, E. faecium, P. nigrescens, T. forsythia, and T. denticola were associated with severe lesions caused by ovine periodontitis, and F. nucleatum was the most prevalent microorganism in the subgengival sulcus biofilm of healthy sheep.(AU)

Periodontite é a resposta inflamatória de um hospedeiro suscetível causada por complexa microbiota, composta predominantemente por bactérias anaeróbias Gram-negativas. Com o objetivo de caracterizar a microbiota bacteriana subgengival associada à periodontite ovina foi realizada a reação em cadeia da polimerase (PCR) de amostras de biofilme subgengival de 14 ovinos com a enfermidade e 14 ovinos periodontalmente saudáveis, com destaque para micro-organismos Gram-negativos e Gram-positivos considerados importantes periodontopatógenos. As bactérias mais prevalentes em 14 animais com lesões periodontais foram Tannerella forsythia (78,6%), Treponema denticola (78,6%), Fusobacterium nucleatum (64,3%) e Porphyromonas gingivalis (50%). Entretanto, nos 14 ovinos sem lesões periodontais, F. nucleatum (42,8%) foi a bactéria mais detectada. Associação estatisticamente diferente foi observada para Campylobacter rectus, Enterococcus faecium, Prevotella nigrescens, T. forsythia e T. denticola (p<0,05) nos ovinos com periodontite em comparação entre os dois grupos. Aggregatibacter actinomycetemcomitans, Enterococcus faecalis e Porphyromonas gulae não foram detectados em nenhuma das amostras pesquisadas. Conclui-se que C. rectus, E. faecium, P. nigrescens, T. forsythia e T. denticola estão associados às lesões resultantes da periodontite ovina com manifestação clínica grave e F. nucleatum o micro-organismo mais prevalente no biofilme subgengival de animais periodontalmente sadios.(AU)

Subgingival bacterial microbiota associated with ovine periodontitis / Microbiota bacteriana subgengival associada à periodontite ovina

Periodontitis is an inflammatory response in a susceptible host caused by complex microbiota, predominantly composed of Gram-negative anaerobic bacteria. Aiming to characterize the subgingival bacterial microbiota associated with ovine periodontitis, polymerase chain reaction (PCR) was performed in subgingival periodontal pocket samples of 14 sheep with severe periodontitis and in subgingival sulcus biofilm of 14 periodontally healthy sheep in search mainly of Gram-negative and Gram-positive microorganisms considered important periodontopathogens. The most prevalent bacteria in the sheep with periodontal lesions were Tannerella forsythia (78.6%), Treponema denticola (78.6%), Fusobacterium nucleatum (64.3%), and Porphyromonas gingivalis (50%), whereas in the healthy sheep, F. nucleatum (42.8%) was the most often detected bacterium. Statistically significant differences were observed for Campylobacter rectus, Enterococcus faecium, Prevotella nigrescens, T. forsythia, and T. denticola (p<0.05) in the sheep with periodontitis in the comparison between groups. Aggregatibacter actinomycetemcomitans, Enterococcus faecalis, and Porphyromonas gulae were not detected in any of the samples analyzed. In conclusion, C. rectus, E. faecium, P. nigrescens, T. forsythia, and T. denticola were associated with severe lesions caused by ovine periodontitis, and F. nucleatum was the most prevalent microorganism in the subgengival sulcus biofilm of healthy sheep.(AU)

Periodontite é a resposta inflamatória de um hospedeiro suscetível causada por complexa microbiota, composta predominantemente por bactérias anaeróbias Gram-negativas. Com o objetivo de caracterizar a microbiota bacteriana subgengival associada à periodontite ovina foi realizada a reação em cadeia da polimerase (PCR) de amostras de biofilme subgengival de 14 ovinos com a enfermidade e 14 ovinos periodontalmente saudáveis, com destaque para micro-organismos Gram-negativos e Gram-positivos considerados importantes periodontopatógenos. As bactérias mais prevalentes em 14 animais com lesões periodontais foram Tannerella forsythia (78,6%), Treponema denticola (78,6%), Fusobacterium nucleatum (64,3%) e Porphyromonas gingivalis (50%). Entretanto, nos 14 ovinos sem lesões periodontais, F. nucleatum (42,8%) foi a bactéria mais detectada. Associação estatisticamente diferente foi observada para Campylobacter rectus, Enterococcus faecium, Prevotella nigrescens, T. forsythia e T. denticola (p<0,05) nos ovinos com periodontite em comparação entre os dois grupos. Aggregatibacter actinomycetemcomitans, Enterococcus faecalis e Porphyromonas gulae não foram detectados em nenhuma das amostras pesquisadas. Conclui-se que C. rectus, E. faecium, P. nigrescens, T. forsythia e T. denticola estão associados às lesões resultantes da periodontite ovina com manifestação clínica grave e F. nucleatum o micro-organismo mais prevalente no biofilme subgengival de animais periodontalmente sadios.(AU)

Efficacy of virginiamycin for the control of periodontal disease in calves / Eficácia da virginiamicina no controle de doença periodontal em bezerros

Periodontal diseases are multifactorial infectious processes caused by complexes of microorganisms, with damage to health, production, and animal welfare. The aim of the present study was to evaluate the efficacy of virginiamycin in the prevention and control of two early forms of periodontal disease: gingivitis and necrotizing gingivitis. Ten weaned calves, aged four to six months, were permanently kept in a single lot under the same rotational grazing regime in a newly reformed area of Panicum maximum. Five of the calves were orally administered 340mg of virginiamycin (Virginiamycin Group) daily for a period of 18 weeks, while the remaining five calves (Control Group) remained under the same food management but did not receive virginiamycin. During this period, animals underwent 18 weekly evaluations regarding periodontal health, with monitoring and recording of clinical parameters of the eight deciduous incisor teeth on the labial and lingual faces. At approximately two-week intervals, nine collections of subgingival sulcus material from five sites of the four right incisor teeth of each animal were performed and subjected to microbiological evaluation using polymerase chain reaction with primers of 25 microorganisms considered potentially pathogenic. After 1440 periodontal clinical evaluations of incisor teeth of the 10 calves, a total of 395 episodes of gingivitis were recorded, of which 267 occurred in the Control Group and 128 in the Virginiamycin Group. Similarly, 89 episodes of necrotizing gingivitis were recorded; 58 in the Control Group and 31 in the Virginiamycin Group. Comparison of between-group means found significant differences for teeth with gingivitis and necrotizing gingivitis (t test; p<0.05). The total number of teeth with gingivitis (p<0.01) and necrotizing gingivitis (p<0.01) in Control Group was significantly higher than that of gingivitis (p<0.01) and necrotizing gingivitis (p<0.05) in the Virginiamycin Group. There was a positive correlation between total occurrence of gingivitis and necrotizing gingivitis in the Virginiamycin Group by Pearson's test. Virginiamycin had a protective effect on treated animals compared with the Control Group (OR = 0.36: CI (95%) = 0.27-0.43). In the Control Group, Actinomyces israelli (4.74%), domain Archaea (1.58%), Eikenella corrodens (1.05%), Fusobacterium nucleatum (27.37%), class Mollicutes (5.26%); Porphyromonas endodontalis(5.26%); Porphyromonas gulae(0.53%), Prevotella buccae (6.32%), Prevotella loescheii (3.68%), Prevotella nigrescens (8.42%), Prevotella oralis (1.58%), Tannerella forsythia (0.53%), and Treponema denticola (4.21%) were detected at healthy sites, and gingivitis or necrotizing gingivitis samples. In the Virginiamycin Group, A. israelli (3.41%), domain Archaea (0.98%), F. nucleatum (9.27%), class Mollicutes(4.39%), P. endodontalis (4.39%), P. gulae (0.49%), P. buccae (8.29%), P. loescheii (6.83%), P. nigrescens (15.61%), P. oralis (1.46%), Selenomonas sputigena (0.49%), T. forsythia (0.49%), and T. denticola (2.44%) were detected. In conclusion, virginiamycin administered at a dosage of 340mg/animal/day significantly reduced the occurrence of gingivitis and necrotizing gingivitis in cattle maintained on reformed pastures, and was revealed to have action against periodontal bacterial microbiota considered to be potentially pathogenic.(AU)

As doenças periodontais são processos infecciosos multifatoriais causados por complexos de micro-organismos, que provocam danos à saúde, produção e ao bem-estar animal. O objetivo do presente estudo foi o de avaliar a eficácia da virginiamicina na prevenção e controle de duas formas de doença periodontal; a gengivite e a gengivite necrosante. Assim, dez bezerros desmamados, com idade entre 4 e 6 meses, foram mantidos permanentemente em lote único e sob o mesmo regime de pastejo rotacionado em área reformada de Panicum maximum. Cinco bezerros receberam via oral 340mg de virginiamicina (Grupo Virginiamicina) diariamente, por um período de dezoito semanas, enquanto o Grupo Controle permaneceu sob o mesmo manejo alimentar, mas sem receber a virginiamicina. No período, os animais passaram por 18 avaliações semanais quanto à saúde periodontal, com monitoramento e registro dos parâmetros clínicos dos oito dentes incisivos decíduos, nas suas faces labial e lingual. Em intervalos aproximadamente quinzenais foram realizadas nove coletas de material do sulco subgengival de cinco sítios de quatro dentes incisivos direitos de cada animal para avaliação microbiológica, com o emprego da reação em cadeia da polimerase e com iniciadores de 25 micro-organismos considerados potencialmente patogênicos. Ao final das 1440 avaliações clínicas periodontais dos dentes incisivos dos dez bezerros, pôde-se registrar um total de 395 episódios de dentes com gengivite, nos quais 267 foram registrados no Grupo Controle e 128 no Grupo Virginiamicina. De forma semelhante, do total de 89 registros de gengivite necrosante, 58 foram no Grupo Controle e 31 no Grupo Virginiamicina. Na comparação entre médias dos grupos as diferenças encontradas para dentes com gengivite e gengivite necrosante foram significativas pelo teste t (p<0,05). Assim, o total de dentes com gengivite (p<0,01) e gengivite necrosante (p<0,01) no Grupo Controle, foi significativamente superior ao de gengivite (p<0,01) e gengivite necrosante (p<0,05) do Grupo Virginiamicina. Houve correlação positiva entre o total de ocorrência de gengivite e gengivite necrosante no Grupo Virginiamicina pelo teste de Pearson. A virginiamicina possuiu um efeito protetor nos animais tratados em comparação com o controle (OR = 0,36: IC (95%) = 0,27-0,43). Na avaliação microbiológica do Grupo Controle foram detectados nas amostras de sítios sadios, com gengivite ou com gengivite necrosante Actinomyces israelli (4,74%), domínio Archaea (1,58%), Eikenella corrodens (1,05%), Fusobacterium nucleatum (27,37%), classe Mollicutes (5,26%), Porphyromonas endodontalis (5,26%), Porphyromonas gulae (0,53%), Prevotella buccae (6,32%), Prevotella loescheii (3,68%), Prevotella nigrescens (8,42%), Prevotella oralis (1,58%), Tannerella forsythia (0,53%) e Treponema denticola (4,21%). Enquanto no Grupo Virginiamicina foram detectados: A. israelli (3,41%), domínio Archaea (0,98%), F. nucleatum (9,27%), classe Mollicutes (4,39%), P. endodontalis (4,39%), P. gulae (0,49%), P. buccae (8,29%), P. loescheii (6,83%), P. nigrescens (15,61%), P. oralis (1,46%), Selenomonas sputigena (0,49%), T. forsythia (0,49%) e T. denticola (2,44%). Em conclusão, a virginiamicina administrada na dosagem de 340mg/animal/dia reduziu significativamente a ocorrência da gengivite e gengivite necrosante em bovinos mantidos em pastos reformados e revelou ter ação frente à microbiota bacteriana periodontal considerada potencialmente patogênica.(AU)